Vertical slab gel electrophoresis is widely used and of much value in nucleic acid sequencing and in the identification of proteins and other species in biological samples. A problem often encountered in these procedures is the difficulty of loading samples into the sample wells formed along the upper edge of the gel. The wells are small in both length and width and it is difficult to visually distinguish the wells from the clear gel material separating the wells. A syringe is generally used to place the samples in the wells, and the unskilled user with inaccurate placement or a nervous hand may inadvertently place the syringe needle in gel material to one side of a well rather than in the well itself, or break a gel partition. In either case, the differentiation between adjacent sample lanes in the gel will be obscured, and this will impair the user's ability to read the gel accurately at the termination of the experiment.